Cool, so this add in between the existing 90° optional twist ("rotated"), right?
You can post a "I made one", or you can send the update code to me (jeremie francois at google mail) and I can get a closer idea :)
Nb: I should also publish an update of the lib, where I added arbitrary curved angles in the arm (the whole is kept flat though, so there is no problem printing it without support). My code was messy though as far as I remember, regarding the origin of the elements.